How to Tell the Age of a Persian Carpet
The art of Persian carpet-making flourished during the Safavid Dynasty -- 1499 to 1722 CE -- when the Persian Empire comprised present-day Iran, Turkey and parts of Africa.
Consequently, Persian carpets are usually considered as ones originating from these regions. Age is a determinant of value, and sellers use techniques to simulate it,so what may appear to be an antique may, on closer inspection, turn out to be far from it. If you suspect your carpet to be older than 50 years -- which is the usual definition of an antique -- examining a variety of characteristics can confirm this.
Determine the carpet's style by consulting an encyclopedia of Persian carpets. Knowing the style can help determine age, because some -- such as Qum or white Kashan -- have been made only since 1920. Do not date the carpet solely by the style; it's common practice to reproduce these styles in modern factories.
Look for signs of wear, damage or repair. An antique rug is likely to have worn pile. It may also have frayed edges and holes. Look for damage that has been repaired. Repairs should be noticeable on the back side of the carpet. Although this won't help to precisely date the carpet, it will help distinguish a forged antique from a real one. A carpet without any signs of wear is more likely to be forged or modern.
Turn the carpet over, place a ruler on the left and count the number of knots in 1 inch. Rotate the ruler 90 degrees and count the number of knots in 1 inch of warp. The number of knots per square inch can help date a carpet, depending on the style. For example, modern Isfahan rugs have a higher KPSI than those woven in the 18th and 19th centuries, which seldom exceed 400 KPSI.
Note the colors. Carpets predating 1920 were colored with vegetable dyes. They have a narrower range of colors than synthetic ones and fade naturally with age. To simulate aging, some manufacturers bleach their carpets. You can distinguish a bleached carpet from a genuine antique one by examining the pile.
Separate the pile and examine the colors, using a magnifying glass. If the carpet is old and the color has worn naturally, you will note a gradual color variation from the base to the top. Alternatively, if the carpet was bleached, there will be a discrete band of color in the middle.